By the end of the decade “digital video will become the single largest way people spend their free time,” Kyncl said. Cisco recently predicted that video will account for 90% of all Internet traffic by 2019.

TV viewing peaked in 2009, and digital is poised to grow “exponentially,” he said. The youngest millennials already watch more digital video than TV — and the time spent with digital is growing by about 25% a year.

Much of the change will be driven by mobie devices. People ages 18-34 spend an average of 40 minutes a day watching mobile video, up 50% over the last year, but their TV viewing in the period dropped by 9%, he noted.

They like the way mobile makes viewing personal. In addition, they like the diversity of options, adding that YouTube “has the biggest library in the world.”The exec predicts that channels on YouTube will grow much the way cable channels did — starting with derivative programming and eventually developing “content you couldn’t find anywhere else.”

Music is another attraction, he says, noting that more than half of teenagers use YouTube as their main source to discover bands and performers.

Kyncl also talked up virtual reality, including videos that work with Google Cardboard’s inexpensive viewers that use mobile phone screens. It makes VR “a better exerience on mobile than on desktop or TV.” Digital is “immersive in a way television never can be.”

And it’s “primed to grow exponentially,” Kyncl said. He cited a recent experiment where Google delivered its Cardboard viewers for free to New York Times subscribers, giving them an opportunity to watch The Displaced, a VR documentary the paper co-produced with Vrse.

Google also is helping others in the ecosystem, including GoPro, which has a new VR video camera called the Odyssey.